I don't build extensions or work on much front end web lately but this reads like Google wants more control over their stuff. The web is becoming less open. > By moving away from HTML-based rendering to a canvas-based rendering, some Chrome extensions may not function as intended on docs.google.com and may need to be updated. > If you are building your own integrations with Google Docs, we recommend using Google Work…
Did you feel the same when Maps went from HTML to Canvas? There is no factual basis for your claims. The simplest and most obvious answer is performance. Docs these days can take 5-10s to fully open, especially with comments and annotations.
As for Google Maps, it is not speedy or snappy by any stretch of the imagination. In fact, it is pretty abysmal in terms of page performance on the web.